Stuttering/Sputtering Issue - Low RPMs

Nismo907

So I've been having an issue with my Z for the past few weeks and I can't seem to pinpoint the issue.

The issue is in the title "Sputtering/Stuttering at low RPMs" regardless of gear.

So it just happened one day about 2-3 weeks ago. I'm gonna clear up a lot of the processes I've been through so far so hopefully I can find a solution.

I've got a '14 370Z sport model. I've modded it with the AEM Cold Air Intake, Stillen Ceramic Coated Headers, Berk Tech Hi-Flow CATs, ARK Exhaust.
More recently I had a tune and everything ran fine. I had to put it away for the winter after having only driven it for 2 weeks after the tune. The issue that came up showed up one day driving from 1 job location to another(about 2-3 weeks ago). No clue what happened. Just acted funny.

So everything that I've done:
- go to the Nissan dealership and(had the tune removed from the tuner and reverted back to factory tune) and updated the firmware on the ECM. Apparently there was an update necessary to fix some issues.
- Put Heet into the fuel as it might have accumulated some water during the winter.... though it was in a garage during the winter.
- Checked my spark plugs, clean.
- Checked my Coil Packs, good.
- Checked my air filters and pre filters. Clean.
- Checked and cleaned my MAF sensors.
- Checked any wires to see if there was any corrosion. All good.

The weird part WAS no check engine light when I first took it to Nissan. After they updated it, I drove it around a bit and it still had the same issue and the check engine light came on and it put into a Limp Mode.

Next day I took off the bumper and cleaned the sensors again, checked to see if there was anything in the sensor, reinstalled after(waited about an hour with the battery unplugged). Started it up, drove it. Does the same thing, but not as harsh or as often. There is no check engine light anymore and I drove it around for like 30-40 minutes at varying speeds up to highway speeds.

So I'm having a hard time trying to narrow down potential issues. I was planning on installing the stock intake again and test it that way. Nissan isn't willing to work with me because of the CAI.

Any ideas?

kenchan

Clean da throttle body?

jchammond

What tune was on it & did you have fresh fuel in the tank before the tune?
I'm sure they would never use any corn (ethanol) in Alaska.

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Nismo907

I thought about the throttle body but it's doubtful. I'll still give it a whirl.

The tune wasn't the issue as it performed fine after the tune. Only up until after the winter did it have issues. Now it wasn't gradual. I went to work and was fine. Hopped in my car to head to another store and it started having the problems.

Anywho. No corn up here. I think it might the AEM electronic tuning module thing. I emailed AEM about the intake and waiting for a response.

I've installed the OEM intakes to see if maybe the sensors are bad or if the little module things are bad.


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Louie cat

I see your in Alaska,is there another dealer that you can cruise to? Sounds like they are incompetent mechanics there. A cold air intake should not be an excuse to not want to work on a vehicle. That should not void a warranty. Just in case if you still have the original air boxes, put them back on before you visit to the new place.
It sounds like a no brainier for a good tech to find the problem,sorry to hear of the issues your having.

Nismo907

Thanks Louie. I was going to have a company called P3(the people who dynoed and tuned my car) take a look at it on Monday. Ultimately I might have to reschedule because I found the problem.

One of the AEM intake electronic module things, maybe even both, are causing the car to read air incorrectly. I found this out by installing the stock intake. It ran fine, then when I connected the little module things, they threw a fit. There's no tears, water damage and nothing smells burnt. So I don't know if AEM covers this. I emailed them last night about it, but probably won't get an answer until sometime next week.

I had the AEM CAI for a little under a year, so hopefully they'll work with me. That or I'm going to have to order a new intake and scrap this one.

Here's the thing:

Thank you everyone for some insight.

Nismo907

https://www.aemintakes.com/search/pr...?prod=41-1001p

This is unit I have. So I don't know if that plays into any effect. All I know is that I might have to look for a new intake.

kenchan

https://www.aemintakes.com/dynochart...-1001_dyno.pdf

hardly any gains. put it back to stock and clean the throttle body

B&W_Evader

How about finish your tank of gas and see how a fresh one acts.

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Kabestro

This is the second place I read this about a firmware update. Do you guys have anymore info. on this? My car sometimes in the morning just turns on in limp mode for no reason. Could this be because of this firmware update?

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Chuck33079

Why would you have the car tuned with the AEM module in place? Why not take it off and have the tuner scale the MAF table for the intake piping diameter, rather than have him tune it for the stock diameter and adjust it with the AEM module?

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Ventruck

Yeah, what in the world. I must know about this.